Process of straightening spindles and the like



Aug. 5, 1920 1,504,024

G. T. CLARK PROCES&,,OF STRAIGHTENING SPINDLES AND THE} LIKE Filed Oct. 5, 1921 s Sheets-Sheet 1 Aug. 5, 1924.; 15%,024

G. T. CLARK PROCESS OF STRAIGHTENING SPINDLES AND THE LIKE Filed Oct. 5, 192] 5 Sheets-Sheet 2 Aug. 5, 1924. 1,504,024 7 G. T. CLARK PROCESS OF STRAIGHTENING SPINDLES AND THE LIKE Filed Oct. 5, 1921 3 Sheets-Sheet 5 Q-il-fi; mm?

if v4 Patented Aug. 5, 1924-.

@NBTED- STATES 1,50%,t2t PATENT QFFEBE.

GEORGE E. CLARK, OF OLD ORCHARD, MAINE, ASSIGNOR T0 SACO LOWELL SHOPS, OF BOSTON, MASSACHUSETTS, A COIt-IPO'RATIUN OF MASSACHUSETTS.

PROCESS OF STRAIGHTENING- SPIN'DLES AND THE LIKE.

7 Application filed October 3, 1921. Serial No. 505,014.

T 0 all whom it may concern:

Be it known that I, GEORGE T. CLARK, a citizen of the United States, residing at Old Orchard, in the county of York and State of Maine, have invented certain'new and useful Improvements in Processes of Straightening Spindles and. the like, of which the following is a specification.

This invention relates to processes of straightening spindles, rods, shafts and similar articles. Since the process provided by this invention is especially valuable in the straightening of spindles used in spinning machines, it will be herein disclosed as ap plied particularly to, the straightening of these articles, but it will be understood that the process is equally applicable to the straightening of other articles, such as those mentioned above, and such articles are regarded as the equivalent of spindles so far as the present process is concerned.

A spinning machine spindle usually has a relatively short cylindrical portion and long tapered parts extending from opposite ends of this cylindrical portion. The manufac turing operations usually consist, roughly speaking, in forging a steel rod into approximately the shape of a spindle, and thus forming what is known as a spindle blank, straightening this blank, and then grinding the blank to the required shape and dimensions. The straightening operation has usually been performed heretofore by placing one end of the spindle blank in a chuck and rotating the spindle rapidly between a series of reversely disposed V-shaped surfaces, this operation being much like that heretofore used extensively in straightening wire. Before the spindle is placed in the chuck it is heated to a dull red heat, and one of the objections to this process has been that the spindle cools oif much more rapidly at the end where it is gripped by the chuck than at other points. This results in hardening the end of the spindle so gripped to an undesirable degree. The present invention aims to devise a process of straightening spindles and the like which will not be open to this objection,but which will cause the spindle to cool ofi substantially uniformly. It is also an object of the invention to devise a process of this character which will be more economical of power than the proc, esses heretofore practised, and which will avoid the reverse bending and mellowing of the steel which is necessarily produced in these prior processes.

The nature of the invention will be readily understood from the following description when read in connection with the accompanying drawings, and the novel features will be particularly pointed out in the appended claims.

Referring now to the drawings,

Figure 1 is a side elevation, partly in cross section, of one form of apparatus with the aid of which the present process may conveniently be practised,

Fig. 2 is a plan View of the apparatus shown in Fig. 1;

Fig. 3 is a vertical cross sectional view through portions of the apparatus shown in Fig. 1, the plane of cross section being taken longitudinally of the spindle; and

Fig. 4 is a diagrammatic View illustrating a feature of the process which will be referred to hereinafter.

The apparatus shown in the drawings forms a part of the straightening machine shown and described in my co-pending application Serial No. 460,863, filed April 13, 1921, and reference should be made to this application for a complete understanding of the machine. This apparatus, and the machine of which it forms a part, forms no part of the present invention but this particular apparatus has been illustrated here because it is a convenient form of apparatus with which the present invention may be practised.

It will be seen from an inspection of Fig. 3 that the spindle S has a short cylindrical part and two tapered portions that extend from opposite ends of this part, the lefthand taper being much shorter than the right-hand taper. The apparatus shown comprises a lower die having an upper face which conforms to the longitudinal contour of the spindle and is made in two sections, indicated at A and B, respectively. Each die section consists of a series of bars 3 secured by screws to a base 4:. The bars preferably are made of steel and the base 4 consists of a steel or iron plate of SLllTlClGllt thickness to be comparatively rigid so that it will hold the bars securely in their proper relationship but still is thin enough to permit it to be flexed or sprung. Both the sections Aand B are secured to a rigid bed 5 by means of clamps 6, Fig. 1, and shims 8,

Fig. 3, are placed between the base plate 4 and the bed 5 to enable the clamps to bend or spring the base suflicientlyto give the desired contour to the die surface formed by the upper edges of the series of bars. The spindle, at this stage of its process of manufacture, does not have a true taper but both tapered parts are bulged or bowed. Consequently, the base members 4 are not straight plates resting on an inclined plane but are each sprung or bent downwardly so that the contour of thesurface of the die conforms 'to, or is a complement of. that of the longitudinal contour of the spindle. This lower die is supported in a fixed position.

Cooperating with the lower die is an upper die which may conveniently consist of a series of relatively heavy bars or arms 10, each having a hardened piece 12 secured to its lower surface. This upper die is reciprocated back and forth horizontally over the lower die by any convenient mechanism, for instance by the parallel motion mechanism indicated in general at 13.

The spindle S to be straightened is placed between the dies, as clearly shown in the drawings, and in order to facilitate the proper positioning of the spindle a gage M may be provided, this gage having a stop 15 to limit the endwise movement of the spindle and abutments 16 between which the spindle is located laterally.

According to this process each spindle to be straightened is heated up to a dull red or cherry red, and the spindle is then placed between the upper and lower dies, as shown in the drawings. The upper die of course is raised to permit the placing of the work in this manner and it is then lowered and the two dies are relatively reciprocated to roll the spindle back and forth between them. Usually it is more convenient to reciprocate the upper die. The upper die presses the spindle against the lower die, this pressure being applied to the spindle at spaced intervals, as will be evident from an inspection of Figs. 2 and 3. The relative movement of the dies not only rotates the spindle about its own axis, but also transfers the spindle bodily back and forth between the dies.

It is obvious that the direction of'rotation of the spindle about its own axis is reversed at the end of each stroke and that the spindle has a momentary pause or period of rest at each end of its stroke. The present invention gives particular attention to the angular positions in which the spindle is stopped during these periods of rest at the opposite ends of its stroke. In this connection it may be stated that it has been proposed heretofore to straighten spindles and the like by rolling them between die surfaces, and while this process may be practised satisfactorily in the straightening of articles which need only a rough straightening, it is not sufficiently accurate for the purpose of straightening spindles, shafts, and similar articles which must straightened accurately. In other words, the mere rolling of the spindle back and forth on the lower die and pressing it against said die by means of another die, will not produce sufficiently accurate or uniformjresults for commercial purposes. Exhaustive tests have demonstrated that while occasionally a spindle treated in this manner maybe straightened, the results are extremely uncertain. I have discovered that the reason for these uncertain results appears to lie in the angular relationship at which the spindle is stopped at the opposite ends'of its stroke.

Referring toFig. 4:, let it be assumed that S indicates the position in which the spindle stops at one end of its stroke, while the direction of motion of the upper die 10 is being reversed. During this period of momentary rest the pressure of the upper die is transmitted through the spindle on the axial plane -.2 7/. If the spindle stops in substantially the same or a diametrically opposite position at the opposite end of its stroke, then the pressure of the die will be transmitted through the spindle on the same plane wg during this period of rest also. The straightening action appears to be greater during these momentary periods of rest than at any other equal period of time during the operation. These spindles of course are only slightly bent when they come to the machine, and if a spindle happens to stop' at the opposite ends of its stroke'on the flat, so to speak, of the curve or bend in it,that is, with the plane of the bend parallel to, the plane of the lower die,the spindle will not be straightened. The spindle of course tends to stop in this position. If, on the other hand, the rotation of the spindle is stopped at the opposite ends of its stroke in substantially different angular positions, as for instance in positions that are 90 apart, as shown in Fig. 4, then the pressure of the upper die will be transmitted through the spindle in a very different axial plane at one end of the stroke from that in which it is transmitted at the opposite end of the stroke. Under these circumstances the spindle will be properly straightened. 7

It will be understood that the foregoing is the explanation which I believe to be correct of the actionthat takes place when the spindle is stopped in different positions. But regardless of what the true explanation may be, I have definitely established that very superior results are obtained when the spindle is stopped at one end of its stroke in an angular position substantially different from that in which it is stopped at ill) the other end of its stroke. The difference in angular position preferably is about 90, but it is not necessarily limited to this angular distance. It should, however, be less than 180 and preferably should be a substantial angular difi erence.

The most convenient way of adjusting this angular relationship is by regulating the length of stroke of the spindle, or, what amounts to the same thing, the length of stroke of the upper die. This may conveniently be done by suitable adjustment of the mechanism through which the reciprocating movement of the upper die is effected in case this die is driven by power, or by the use of suitable stops to limit the movement of the upper die in case this die is moved by hand.

The spindle is rolled back and forth be tween the dies until it has cooled off to such a degree that there is no danger of it being accidentally bent from ordinary handling when it is removed from the apparatus. In order to facilitate this cooling operation the lower die may sit in a water pan 17 as shown, and the lower part of the die may be submerged in water.

It will now be appreciated that this invention provides a very simple process of straightening spindles, and similar articles, which requires very little power, which can be performed with very simple apparatus, and in which the entire spindle cools off substantially uniformly. This process has the further advantage of avoiding the reverse bending of the spindle, with the consequent abuse of the structure of the metal of which the spindle is made, that necessarily is produced in the straightening processes more commonly practiced. Since the straightening operation is performed while the spindle is heated sufficiently to yield to the action of the dies, and the spindle cools down while the dies are still rolling it back and forth, it follows that the molecular set takes place only after the spindle has been straightened. Consequently, there is no biased molecular condition in the spindle, as there probably would be if it were straightened while cold.

Such a condition would be very likely to assert itself after the spindle is put into operation and would cause a partial return of the spindle to its original molecular condition, due, in some measure, to the high speed at which these spindles are operated, and partly, also, to the vibration of the machine. This would result in excessive vibration of the spindle.

It will also be .understood that while I have described my present process in connection with the machine shown in my prior application, since this machine provides a very convenient means for practicing the process, the process nevertheless is entirely independent of any given machine or piece of apparatus, and it may be practised with the aid of a great variety of forms of apparatus differing substantially from each other.

Having thus described my invention, what I desire to claim as new is:

1. That improvement in the art of straightening spindles and the like, which consists in rotating a spindle alternately in opposite directions between suitable dies while pressing said spindle between the dies, and stopping the rotation of the spindle at the end of each period of rotation, and while its direction of rotation is being reversed, in an angular position which causes the pressure exerted thereon by the dies to be transmitted therethrough in a different plane from that in which it was transmitted through the spindle at the end of the previous period of rotation.

2. That improvement in the art of straightening spindles and the like, which consists in rotating a spindle alternately in opposite directions between suitable dies by relatively reciprocating said dies while pressing said spindle between the dies, and stopping the rotation of the spindle momentarily at the ends of its periods of rotation, and while its direction of rotation is being reversed, in positions that difler from each other by a substantial angle but by less than 180.

3. That improvement in the art of straightening spindles and the like, which consists in heating a spindle sufficiently to facilitate the straightening operation, rotating said spindle alternately in opposite directions between suitable dies by relatively reciprocating said dies while pressing said dies one toward the other, and stopping the rotation of the spindle momentarily at the ends of its periods of rotation, and while its direction of rotation is being reversed, in positions that differ from each other by a substantial angle but by less than 180.

4. That improvement in the art of straightening spindles and the like, which consists in heating a spindle sufficiently to facilitate the straightening operation, rolling the spindle back and forth on a rigid surface while in said heated condition, pressing said spindle against said surface while it is being so rolled back and forth, adjusting the stroke of the spindle to stop it at the opposite ends of its stroke in positions having an angular difference of approximately 90", and allowing the spindle to cool off while it is being so rolled back and forth.

5. That improvement in the art of straightening spindles and the like, which consists in heating a spindle sufiiciently tofacilitate the straightening operation, rolling the spindle back and forth while in said heated condition-on a rigid surface conforming substantially to the longitudinal contour of the spindle, maintaining a yielding pressure at spaced intervals on said spindle while it is being so rolled, and stopping said spindle at the opposite ends of its stroke in angular positions that differ from each other substantially but by less than 180.

6. That improvement in the art of straightening spindles and the like, which consists in heating a spindle sufliciently to facilitate the straightening operation, rotating'said spindle alternately in opposite directions between suitable dies by relatively reciprocating said dies while pressing said spindle between them stopping the spindle between successive periods of rotation, and

while its direction of rotation is being reversed, in angular positions which cause the pressure exerted 011 the spindle by the dies during its periods of rest to be transmitted through the spindle in different planes, and allowing the spindle to cool olf while it is being so rotated. V

' GEORGE T. CLARK.

Certificate of Correction.

It is hereby certified that in Letters Patent No. 1,504,024, granted August 5, 1924-, upon the application of George T. Clark, of Old Orchard, Maine, for an improvement in Processes of Straightening Spindles and the like} an error appears in the printed specification requiring correction as follows: Page 3, line 106, claim 3, for the Words dies one toward the other read spindle between the (lies; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 14th day of October, A. D. 1924.

[SEAL-1 KARL FENNING,

' Acting Commissioner of Patents, 

